libstdc++-v3/testsuite/std/ranges/view.cc

   1 // Copyright (C) 2019-2024 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-do compile { target c++20 } }
  19
  20 #include <ranges>
  21 #include <span>
  22 #include <string_view>
  23 #include <experimental/string_view>
  24 #include <vector>
  25 #include <vector>
  26 #include <set>
  27 #include <unordered_set>
  28 #include <regex>
  29 #include <testsuite_iterators.h>
  30
  31 static_assert(std::ranges::view<std::span<int>>);
  32 static_assert(std::ranges::view<std::span<int, 0>>);
  33 static_assert(std::ranges::view<std::span<int, 1>>); // Changed with P2325R3
  34 static_assert(std::ranges::view<std::string_view>);
  35 static_assert(std::ranges::view<std::experimental::string_view>);
  36
  37 static_assert(!std::ranges::view<std::vector<int>>);
  38 static_assert(!std::ranges::view<const std::vector<int>>);
  39 static_assert(!std::ranges::view<std::initializer_list<int>>);
  40 static_assert(!std::ranges::view<const std::initializer_list<int>>);
  41 static_assert(!std::ranges::view<std::set<int>>);
  42 static_assert(!std::ranges::view<const std::set<int>>);
  43 static_assert(!std::ranges::view<std::multiset<int>>);
  44 static_assert(!std::ranges::view<std::unordered_set<int>>);
  45 static_assert(!std::ranges::view<std::unordered_multiset<int>>);
  46 static_assert(!std::ranges::view<std::cmatch>);
  47
  48 // const test_random_access_range<T> is not a range:
  49 static_assert(!std::ranges::view<__gnu_test::test_random_access_range<int>>);
  50
  51 template<typename T>
  52 struct test_view
  53 : __gnu_test::test_random_access_range<T>, std::ranges::view_base
  54 { };
  55
  56 static_assert(std::ranges::view<test_view<int>>);
  57
  58 template<>
  59 constexpr bool std::ranges::enable_view<test_view<long>> = false;
  60
  61 static_assert(!std::ranges::view<test_view<long>>);
  62
  63 void
  64 test01()
  65 {
  66   // Verify LWG 3549 changes to ranges::enable_view.
  67   using std::ranges::view_interface;
  68
  69   struct v1
  70     : __gnu_test::test_random_access_range<int>, view_interface<v1> { };
  71   static_assert(!std::derived_from<v1, std::ranges::view_base>);
  72   static_assert(std::ranges::enable_view<v1>);
  73
  74   struct v2 : v1, view_interface<v2> { };
  75   static_assert(!std::derived_from<v2, std::ranges::view_base>);
  76   static_assert(!std::ranges::enable_view<v2>);
  77
  78   struct v3 : __gnu_test::test_random_access_range<int> { };
  79   static_assert(!std::derived_from<v3, std::ranges::view_base>);
  80   static_assert(!std::ranges::enable_view<v3>);
  81
  82   struct v4 { };
  83   static_assert(!std::ranges::enable_view<view_interface<v4>>);
  84 }